(1) Field of the Invention
This invention relates to light emitting diodes (LED), in particular to LED displays.
(2) Brief Description of Related Art
FIG. 1 shows a prior art 8xc3x978 LED display panel. The two electrodes of each LED is coupled to a pair of soldering pads which are mounted on a substrate 01. Each soldering pad is connected by printed wiring 05 to plated-through holes 04 for connection to the bottom side of the substrate 01. Such printed wiring 05 have irregular pattern printed on the substrate 01.
FIG. 2 shows the bottom side of the substrate 01, again showing the irregularity of the wiring pattern.
The irregularity of the layout does not allow for design flexibility. When the dimension of the display panel is changed, a new layout must be patterned. The mating between the LED display panel and the motherboard does not follow any regular rule, and makes it more difficult to test. If any one of the LEDs is defective, the whole display panel must be discarded.
An object of this invention is to provide a LED display panel, which is partitionable and configurable to different number of pixels. Another object of this invention is to disable any defective LED in a display panel. Still another object of this invention is to provide a LED display panel, which can easily be tested.
These objects are achieved by arranging the LEDs of a display as a matrix array. The metal interconnections for accessing the LEDs of the matrix array are laid out as vertical columns and horizontal rows as in a two-dimensional random access memory array. These matrix array can be cut and partitioned to reduce the number of pixels of the display panel, or be expanded to increase the number of pixels. The partitioned sub-arrays can be pieced together by aligning the corresponding interconnections and connecting them through a motherboard. Any defective LED in the array can be inactivated by not accessing the particular defective LED. The LEDs can be mounted on plated-through holes to reach the opposite side of the substrate for surface mounting to a motherboard.